Sepsis: qSOFA More Accurate Than Previous Criteria in ED

Nicola M. Parry, DVM

January 19, 2017

In the emergency department (ED) setting, the quick Sequential Organ Failure Assessment (qSOFA) score is better than previous criteria for predicting in-hospital mortality among patients with suspected infection, a new study suggests.

Yonathan Freund, MD, PhD, from Pitié-Salpêtrière University Hospital, Paris, France, and colleagues published the results of their multicenter prospective cohort study online January 17 in JAMA.

"Among patients presenting to the [ED] with suspected infection, the use of qSOFA resulted in greater prognostic accuracy for in-hospital mortality than did either SIRS [systemic inflammatory response syndrome] or severe sepsis [criteria]," the authors write.

In 2016, a task force of experts was convened to redefine sepsis in the Third International Consensus Definitions for Sepsis and Septic Shock (Sepsis-3). In the previous guideline, the definition of sepsis was based on SIRS criteria, which are nonspecific. In Sepsis-3, the experts redefined sepsis as life-threatening organ dysfunction resulting from a dysregulated host response to infection.

In patients with infection, organ dysfunction is now be identified by an increase in the SOFA score of at least 2 points. The experts recommend that clinicians use qSOFA in settings such as the ED to more rapidly identify patients with sepsis. 

Dr Freund and colleagues therefore set out to prospectively validate qSOFA as a mortality predictor in the ED and to compare the accuracy of the new criteria with both the previously used SIRS criteria and the previous definition of severe sepsis (namely, at least two elements of SIRS and a blood lactate level of more than 2 mmol/L (18 mg/dL).

They conducted the study during a 4-week period in 30 EDs in France, Switzerland, Spain, and Belgium, including adult patients with a suspicion of infection who visited the recruiting EDs. Patients were screened and followed until death or hospital discharge.

For each patient, the ED physician recorded the three components of the qSOFA at their worst level during the ED stay (highest respiratory rate, lowest systolic blood pressure, and lowest Glasgow Coma Scale score). The presence of an altered mental status was also recorded independent of Glasgow Coma Scale.

The analysis included 879 patients with a median age of 67 years; 414 (47%) were women. Respiratory tract was the most common site of infection (n = 379; 43%).

"Overall, in-hospital mortality was 8%," the authors note. Patients with a qSOFA score lower than 2 had a 3% mortality rate (95% confidence interval [CI], 2% - 5%), whereas those with a score of 2 or higher had a 24% mortality rate (95% CI, 18% - 30%; absolute difference, 21% [95% CI, 15% - 26%]).

The researchers found qSOFA to be better at predicting in-hospital mortality (area under the receiver operating curve [AUROC], 0.80; 95% CI, 0.74 - 0.85) than the SIRS criteria (AUROC, 0.65; 95% CI, 0.59 - 0.70) and severe sepsis criteria (AUROC, 0.65; 95% CI, 0.59 - 0.70; P < .001 compared with qSOFA).

qSOFA had a sensitivity of 70% (95% CI, 59% - 80%) and specificity of 79% (95% CI, 76% - 82%) for prediction of in-hospital mortality. The test had a positive likelihood ratio of 3.40 (95% CI, 2.80 - 4.17) and a negative predictive value of 97% (95% CI, 95% - 98%).

After adjusting for patient age and site of infection, a qSOFA of 2 or higher was associated with in-hospital mortality with a hazard ratio (HR) of 6.2 (95% CI, 3.8 - 10.3; Harrell C, 0.83). In comparison, using the previous definition of severe sepsis, the HR was 3.5 (95% CI, 2.2 - 5.5).

"One of the strengths of this study is that it prospectively validates the [task force's] findings and highlights how these findings particularly apply to ED patients with even stronger results," the authors conclude.

An accompanying editorial emphasizes the importance of timely identification of patients with possible sepsis.

"[C]linicians must rely on clinical judgment, potentially augmented by clinical criteria validated to identify sepsis among patients with infection," write François Lamontagne, MD, from the University of Sherbrooke, Canada, and David A. Harrison, PhD, and Kathryn M. Rowan, PhD, both from the Intensive Care National Audit & Research Centre, London, United Kingdom.

According to the editorialists, studies have mainly used predictive validity to assess qSOFA. They highlight one particular study of patients with suspected infection that compared use of qSOFA with use of the more complex SOFA or Logistic Organ Dysfunction System tests for patient encounters in hospital settings. In the intensive care unit setting, qSOFA had a worse predictive validity for in-hospital mortality than SOFA or the Logistic Organ Dysfunction System had. However, outside the intensive care unit, qSOFA had a similar or better predictive validity than the other two tests had, despite its relative simplicity.

Although the editorialists acknowledge that qSOFA could therefore be most useful outside the intensive care unit, they stress that the test still needs further evaluation in other settings. For example, in some settings, factors such as how quickly patients with a suspected infection present to the hospital might vary substantially and could affect the test's predictive validity.

Dr Lamontagne and colleagues also suggest that use of qSOFA could be replaced by any highly accurate, rapid diagnostic tests for sepsis that might emerge. However, at least for now, "qSOFA appears a simple, rapid, inexpensive, and valid way to identify — among patients with suspected infection — those at a higher risk of having or developing sepsis," they conclude.

Dr Freund received lecturer fees from Daichi-Sankyo. One coauthor received personal fees from ThermoFisher Brahms, CrossJect, Sanofi, and LFB. Dr Lamontagne served as investigator for a study funded by GlaxoSmithKline and E-Motion, both of which funded remuneration of research staff. The other coauthors and editorialists have disclosed no relevant financial relationships.

JAMA. 2017;317:267-268, 301-308. Article abstract, Editorial extract

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